Stereolithography Patent Issues

From: Hubert Aunkofer (
Date: Tue Jan 30 1996 - 10:40:59 EET

Yakov Horenstein wrote (18th January):

>I think that this announcement means that 3D Systems have won one of their
patent infringement suits against the Germany company (EOS).

This is a completely false interpretation. 3D Systems has never won any patent
infringement suit against EOS or any users of EOS technology, despite trying
hard for over two years.

In 1993 3D Systems started a legal challenge against EOS relating to alleged
infringement of the European patent EP 0 171 069, which covers the so-called
deep-dip method of recoating in stereolithography. This litigation is pending
before the District Court Munich 1. According to European patent law, in order
to win the case 3D Systems must prove that EOS machines used the deep-dip method
after the patent came into effect. 3D Systems has been unable to prove this so
far because the STEREOS active recoating method (see below), which does not
involve any deep-dip, was introduced and fitted into all installed machines
before the patent was granted.

3D Systems has also challenged EOS regarding alleged infringement of claims
relating to the doctor blade of 3Ds German utility model G 89 16 116.5. EOS
petitioned for cancellation of this utility model, whereupon the court
proceedings were suspended pending a final decision on the legal validity of the
utility model. The German Patent Office examined the utility model and in the
first instance cancelled it completely.

In 1995 EOS received orders for 40 STEREOS and EOSINT machines and thereby
substantially increased our market share. Sales of both STEREOS and EOSINT
systems increased very significantly. Our experience is that customers base
their purchasing decision on the relative technical and economical performance
of the available systems, and after studying the patent issues consider them not
to be a significant problem. Our recent customers include a number of companies
whose own patent and legal departments have studied the issues before purchasing
EOS equipment.

To date EOS has been granted 19 patents and 12 utility models relating to our
own rapid prototyping inventions and holds exclusive licences to two other rapid
prototyping patents.

E. Derek Smith wrote (18th January):

>I believe the system in question had an active recoating system,
incorporating technology that may have a profound impact on build cycle time and
trapped volume success. What have the development engineers and lawyers done
with all this?

Correct. All STEREOS stereolithography systems from EOS have been using active
recoating since 1993. This means that the new resin is actively applied from
above, so that the partly-built model only has to be lowered by exactly the
required layer thickness into the vat, a single movement which eliminates the
need for a deep-dip.

STEREOS MAX 600 uses a computer-controlled pump to precisely regulate the volume
and rate of applied resin, and also has adaptive recoating control which can
vary the rate of resin application within each recoating cycle. This enables
some of the problems commonly encountered with other recoating systems,
particularly closed volume effects, to be greatly reduced or eliminated and
leads to much improved process reliability. This in turn leads to shorter
recoating times and therefore faster part building. The recoater is also
bidirectional and can make a full recoating cycle in one single traverse of the
vat, thereby effectively halving the recoating time.

Mike Shellabear

Pasinger Strasse 2
D-82152 Planegg/Munchen, Germany

Tel. +49 89 8991310
Fax.: +49 89 8598402

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